ABSTRACT
METRIC [Mapping Evapotranspiration at High Resolution with Internalized Calibration] is known as an appropriate surface energy balance model for the estimation of the spatial distribution of evapotranspiration [ET] in semi-arid regions. Based on lysimeter measurements, METRIC has shown ET estimates of 10% on a sub-field scale on a daily basis. There is a need to identify how the model is sensitive to the input parameters. Therefore, the most influential parameters in the algorithm can be identified and the model can be further improved. Sensitivity analysis at three levels of vegetation cover shows that METRIC is highly sensitive to dT, surface temperature, net radiation, sensible heat flux, surface albedo, soil heat flux, and air temperature. It is also moderately sensitive to friction velocity, aerodynamic resistance to heat transfer, surface emissivity and less sensitive to leaf area index, soil adjusted vegetation index, wind speed [except wind speed at low level of vegetation cover][4], and roughness length for momentum [except Z[om]<0.1]. A two-factor analysis of the algorithm's primary inputs showed that the pair albedo-surface temperature is the most and the normalized vegetation index-soil adjusted vegetation index or normalized vegetation index-leaf area index is the least effective pair in this model. In order to improve the accuracy of METRIC, this study suggests upgrading the equations for the above-mentioned effective variables
ABSTRACT
Transmission of infection via multiple dose vials has been well documented. Thus, the probability of contamination in these vials, no matter how little, is very important because they are supposed to be a potential source of nosocomial infection in patients. Therefore, a prevalence study on the contamination of multiple dose vials [MDV] seams to be necessary. The purpose of this study was to identify bacterial contamination and red blood cell [RBC] contamination in multiple dose vials used in Bahman 22 [nd] Hospital. In a cohort study, different types of MDVs used in different sections of Bahman 22[nd] Hospital were periodically collected during one year. Information about the medication, wards, labeling of vials, the date and time of opening and storing temperature was recorded. Then, 0.5 ml of each vial was cultured in Blood Agar media at 37[degree sign] c for 48 hours. Also, the samples were tested for Red Blood Cell contamination after they were centrifuged. Totally, 300 MDV's were collected and studied. No bacterial contamination was found in the cultures. Of the 300 vials available, 2 vials were contaminated with RBC [2 RBC in one vial and 3 RBC in another] at a contamination rate of 0.67%. Although the results of bacterial culture of multiple dose vials used in different wards of the hospital were negative, the contamination of two vials with Red Blood Cells is still very important. The findings should raise concerns about the potential risk of transmission of blood borne pathogens through such vials